chapter 4 & 5 questions

Unlike the C regions of immunoglobulin heavy-chain loci, the C regions of the T-cell receptor β-chain loci

are functionally similar

_____ is secreted into the bloodstream, whereas _____ is secreted into mucus such as gastrointestinal fluid, colostrum, saliva, tears, and sweat.

monomeric IgA: dimeric IgA

In contrast with leader peptides and the C regions, the V regions in immunoglobulin heavy-chain genes

. are composed of V, D, and J gene segments that must undergo gene rearrangement to generate a transcribable exon

Which of the following statements is correct concerning membrane-coding (MC) exons of immunoglobulin genes?

MC exons specify transmembrane hydrophobic amino acids that associate with the B-cell membrane.

Identify which of the following statements is true regarding the transporter associated with antigen processing (TAP).

TAP is an ATP-dependent, membrane-bound transporter.

The degradation of pathogen proteins into smaller fragments called peptides is a process commonly referred to as

antigen processing

The amino-terminal regions of heavy and light chains of different immunoglobulins all differ in amino acid sequence. true or false

true

The heavy-chain constant region is responsible for the effector function of immunoglobulins true or false

true

_ T cells require an accessory cell called an antigen-presenting cell, which bears MHC molecules on its surface true or false

true

All of the following are primarily associated with CD4 T-cell function except

kill virus-infected cells

The T-cell receptor has structural similarity to an immunoglobulin Fab fragment.

true

Which of the following statements about the production and use of monoclonal antibodies is incorrect?

. Production of monoclonal antibodies requires a purified form of antigen.

IgG possesses _______ binding sites for antigen, and the T-cell receptor possesses _______ binding sites for antigen:

2; 1

How many complementarity-determining regions contribute to the antigen-binding site in an intact T-cell receptor?

6

Identify the correct order of gene segments in a rearranged heavy-chain gene in a naive B cell.

L-VDJ-Cμ-Cδ

Which of the following does not describe B-cell receptors?

B-cell receptors lack specificity and can bind to a number of different antigens.

Production by the patient of antibodies against therapeutic mouse monoclonal antibodies is the major limitation for their use in humans. These human anti-antibodies are directed against the _____ of the mouse antibody.

C regions

Which of the following is not a term used to describe the molecules or components of molecules to which antibodies bind? (Select all that apply.)

CDR loops hypervariable region

Which of the following describes two recombination signal sequences required for a permitted somatic recombination event?

DH 7-12-9::9-23-7 JH

Which of the following statements regarding Omenn syndrome is incorrect?

It is the consequence of complete loss of RAG function.

The antibody transported across mucosal epithelia is _____:

IgA

Which immunoglobulin is transported most efficiently across mucosal epithelium?

IgA

The five classes (isotypes) of immunoglobulins comprise

IgA, IgD, IgE, IgG, IgM

A newborn derives passive immunity from its mother as a result of placental transfer of _____ during pregnancy

IgG

Which of the following can be found in serum in a monovalent form?

IgG4

All of the following are required for isotype switching except

J chain

Antigen processing involves the breakdown of protein antigens and the subsequent association of peptide fragments on the surface of antigen-presenting cells with

MHC class I or class II molecules

The primary reason for transplant rejections is due to differences in _____ between donor and recipient.

MHC molecules

Junctional diversity during gene rearrangement results from the addition of

P and N nucleotides

Identify the incorrect statement regarding flow cytometry.

Samples must consist of a single cell type and not be composed of multiple cell types.

Which of the following characteristics is common to both T-cell receptors and immunoglobulins?

Somatic recombination of V, D, and J segments is responsible for the diversity of antigen-binding sites.

Which of the following best describes the function of tapasin?

Tapasin is a bridging protein that binds to both TAP and MHC class I molecules and facilitates the selection of peptides that bind tightly to MHC class I molecules.

Which of the following is not a component of V(D)J recombinase?

Terminal deoxynucleotidyl transferase

If viewing the three-dimensional structure of a T-cell receptor from the side, with the T-cell membrane at the bottom and the receptor pointing upwards, which of the following is inconsistent with experimental data?

The portion that makes physical contact with the ligand comprises Vβ and Cβ, the domains farthest from the T-cell membrane.

In what way does the κ light chain differ from the λ light chain?

The κ locus encodes a single C segment, whereas the λ locus has more than one.

Which of the following is not a characteristic of immunoproteasomes?

They produce a higher proportion of peptides containing acidic amino acids at the carboxy terminus compared with constitutive proteasomes.

The enzyme responsible for recombining V, D, and J segments during somatic recombination is called

V(D)J recombinase

The immunoglobulin heavy-chain gene consists of _______ segments, whereas the immunoglobulin light-chain gene consists of _______ segments.

VDJ; VJ

The most variable parts of the T-cell receptor are

Vα and Vβ

The antigen-recognition site of T-cell receptors is formed by the association of which of the following domains?

Vα and Vβ.

Which of the following statements regarding CD8 T cells is incorrect?

When activated, CD8 T cells in turn activate B cells.

T-cell receptors structurally resemble

a single Fab of immunoglobulins

In B cells, transport of immunoglobulin to the membrane is dependent on association with two invariant proteins, Igα and Igβ. Which of the following invariant proteins provide this function for the T-cell receptor in T cells?

a. CD3γ b. CD3δ c. CD3ε d. ζ *e. All of the above.*

A circulating B cell that has never before encountered antigen expresses _____ on the cell surface:

a. IgM and IgD

4-29 Indicate which of the following statements is false. (Select all that apply.)

a. Immunoglobulin heavy- and light-chain loci are encoded on the same chromosome.

Which of the following statements regarding immunoglobulins is correct?

a. Immunoglobulins make up five classes (or isotypes) called IgA, IgD, IgE, IgG, and IgM.

Which of the following statements regarding Igα and Igβ proteins are correct? (Select all that apply.)

a. They associate with all isotypes of antibodies on the cell membrane. c. They facilitate signal transduction through their long cytoplasmic tails. d. They are linked to one another by disulfide linkages.

The process used to produce either surface or secreted forms of the immunoglobulin heavy chain is called

a. alternative RNA processing

The _______ contribute to antigen specificity of immunoglobulins, and _______ make up the more conservative flanking regions.

a. hypervariable loops; framework regions

Which of the following is mismatched?

affinity maturation: isotype switching

IgM and IgD are co-expressed on naive B cells by a process called

alternative mRNA splicing

Which of the following statements regarding immunoglobulin light chains is correct?

b. There is no functional difference between κ and λ.

Which of the following corresponds to the antigen-binding site of immunoglobulins?

b. VH:VL

_____, _____, and _____ are the three most abundant antibodies in blood:

c. IgA, IgG, and IgM

Which immunoglobulin's main function is to mediate sensitization of mast cells?

c. IgE

4-50 Naive B cells are recognized by their expression of

c. both IgM and IgD on the cell surface

A _____ antibody is one that facilitates a chemical reaction involving the antigen to which it binds and interacts.

c. catalytic

The process of _____ results in change in the constant region of the heavy-chain of antibodies, causing a change in the effector function and transport properties of antibodies:

c. isotype switching

All of the following are included in the peptide-loading complex except

calnexin

The process of _____ results in the amplification of particular B cells with specificity for antigen:

clonal selection

_______ forms dimers, whereas _______ forms pentamers.

d. IgA; IgM

Which of the following does not activate complement? (Select all that apply.)

d. IgG4 f. IgE h. IgD.

Which of the following enzymes facilitates the process of affinity maturation?

d. activation-induced cytidine deaminase (AID)

As an adaptive immune response progresses, the production of variant antibodies that compete more effectively for antigen occurs, and B cells producing these antibodies are preferentially selected on the basis of their improved binding to antigen. This phenomenon is referred to as _______.

d. affinity maturation

4-33 Which of the following is matched incorrectly?

d. affinity maturation: addition of P and N nucleotides

Another term commonly used to describe hypervariable loops is

d. complementarity-determining regions

Neutralizing antibodies

d. inhibit interaction of antigen with human cell surfaces

Which of the following determines the isotype of an immunoglobulin?

d. its heavy chain

Identify which of the following is not associated with activation-induced cytidine deaminase (AID) activity.

diversification of the VH domain but not the VL domain

Which of the following is mismatched?

e. four C domains: IgM and IgD.

All of the following statements regarding γ:δ T cells are correct except

expression on the cell surface is not dependent on the CD3 complex.

A flexible hinge region holds the heavy chain and light chain together. true or false

false

T cells and B cells recognize the same types of antigen true or false

false

T cells and B cells require MHC molecules for the recognition of peptide antigens. true or false

false

T-cell receptor and immunoglobulin genes are encoded on the MHC.

false

The antibody secreted by a plasma cell has a different specificity for antigen than the immunoglobulin expressed by its B-cell precursor. true or false

false

__λ and κ light chains have different functions. true or false

false

T cells recognize antigen when the antigen

forms a complex with membrane-bound MHC molecules on another host-derived cell

With the exception of B cells, all other cells of the body have the immunoglobulin genes in the

germline configuration

The five isotypes of immunoglobulin differ from each other in their _____:

heavy-chain constant regions

The highest degree of diversity resulting from somatic recombination is concentrated ____________ of the VH and VL domains, whereas the point mutations caused by somatic hypermutation are found ____________.

in CDR3; throughout the V region

All of the following are utilized in the binding of antibodies to antigens except

interchain disulfide bonds

Which of the following is not a characteristic of native antigen recognized by T cells?

not requiring degradation for recognition

When describing the various components of the vesicular system, which of the following is not included?

nucleus

The name given to a fully activated and differentiated B cell that secretes antibody is

plasma cell.

Which one of the following features renders all IgG antibodies less susceptible to proteolysis than the other antibody classes?

presence of additional disulfide bonds

In contrast to immunoglobulins, α:β T-cell receptors recognize epitopes present on _______ antigens:

protein

The mechanisms contributing to peptide editing include which of the following? (Select all that apply.)

removal of amino acids from the amino-terminal end by endoplasmic reticulum aminopeptidase (ERAP) c. the participation of tapasin in finding a 'good fit' for class I heterodimers d. recycling an MHC class I heterodimer if the peptide falls out of its peptide-binding groove

The mutational mechanism that results in the production of antibodies that bind antigen with higher affinity is called _____:

somatic hypermutation

All of the following processes occur in mature B cells after antigen encounter except

somatic recombination

The process of gene rearrangement in immunoglobulin and T-cell receptor genes is called

somatic recombination

Unlike B cells, T cells do not engage in any of the following processes except

somatic recombination

The enzyme responsible for adding N nucleotides is

terminal deoxynucleotidyl transferase

On the heavy-chain immunoglobulin gene locus, recombination signal sequences flank _______ of the V segment, _______ of the D segment, and _______ of the J segment.

the 3′ side; both sides; the 5′ side.

When comparing the T-cell receptor α-chain locus with the immunoglobulin heavy-chain locus, all of the following are correct except

the T-cell receptor α-chain locus contains more C regions

Which of the following statements regarding T-cell receptor recognition of antigen is correct?

α:β T-cell receptors recognize antigen only as a peptide bound to an MHC molecule.

Owing to the location of the δ-chain locus of the T-cell receptor on chromosome 14, if the _______-chain locus rearranges by somatic recombination, then the δ-chain locus is _______:

α; deleted

All of the following comprise heavy-chain isotypes of immunoglobulin except

β

During T-cell receptor _____-gene rearrangement, two D segments may be used in the final rearranged gene sequence, thereby increasing overall variability of this chain.

δ

In terms of V, D, and J segment arrangement, the T-cell receptor α-chain locus resembles the immunoglobulin _______ locus, whereas the T-cell receptor β-chain locus resembles the immunoglobulin _______ locus:

κ light chain; heavy chain